Dear all： I've simply try to compile the example file fpi.f with g95 compiler. My OS is Windows 7 64 bits. Therefore, I use 1.4.1p1 x86_64 version of MPICH2. And I got errors listed below: C:\Program Files\MPICH2\examples>g95 -I"C:/Program Files/MPICH2/include" -L"C:/Program Files/MPICH2/lib" fpi.f -lfmpich2g C:\Users\Troy\AppData\Local\Temp/ccUROg3z.o:fpi.f:(.text+0x1e): undefined reference to `mpi_init__' C:\Users\Troy\AppData\Local\Temp/ccUROg3z.o:fpi.f:(.text+0x42): undefined reference to `mpi_comm_rank__' C:\Users\Troy\AppData\Local\Temp/ccUROg3z.o:fpi.f:(.text+0x66): undefined reference to `mpi_comm_size__' C:\Users\Troy\AppData\Local\Temp/ccUROg3z.o:fpi.f:(.text+0x248): undefined reference to `mpi_bcast__' C:\Users\Troy\AppData\Local\Temp/ccUROg3z.o:fpi.f:(.text+0x3a9): undefined reference to `mpi_reduce__' C:\Users\Troy\AppData\Local\Temp/ccUROg3z.o:fpi.f:(.text+0x465): undefined reference to `mpi_finalize__' C:\Users\Troy\AppData\Local\Temp/ccUROg3z.o:fpi.f:(.data+0x0): undefined reference to `mpi_comm_dup_fn__' C:\Users\Troy\AppData\Local\Temp/ccUROg3z.o:fpi.f:(.data+0x4): undefined reference to `mpi_comm_null_delete_fn__' C:\Users\Troy\AppData\Local\Temp/ccUROg3z.o:fpi.f:(.data+0x8): undefined reference to `mpi_conversion_fn_null__' C:\Users\Troy\AppData\Local\Temp/ccUROg3z.o:fpi.f:(.data+0xc): undefined reference to `mpi_dup_fn__' C:\Users\Troy\AppData\Local\Temp/ccUROg3z.o:fpi.f:(.data+0x10): undefined reference to `mpi_comm_null_copy_fn__' C:\Users\Troy\AppData\Local\Temp/ccUROg3z.o:fpi.f:(.data+0x14): undefined reference to `mpi_null_copy_fn__' C:\Users\Troy\AppData\Local\Temp/ccUROg3z.o:fpi.f:(.data+0x18): undefined reference to `mpi_null_delete_fn__' C:\Users\Troy\AppData\Local\Temp/ccUROg3z.o:fpi.f:(.data+0x1c): undefined reference to `mpi_type_dup_fn__' C:\Users\Troy\AppData\Local\Temp/ccUROg3z.o:fpi.f:(.data+0x20): undefined reference to `mpi_type_null_delete_fn__' C:\Users\Troy\AppData\Local\Temp/ccUROg3z.o:fpi.f:(.data+0x24): undefined reference to `mpi_win_dup_fn__' C:\Users\Troy\AppData\Local\Temp/ccUROg3z.o:fpi.f:(.data+0x28): undefined reference to `mpi_win_null_copy_fn__' C:\Users\Troy\AppData\Local\Temp/ccUROg3z.o:fpi.f:(.data+0x2c): undefined reference to `mpi_win_null_delete_fn__' C:\Users\Troy\AppData\Local\Temp/ccUROg3z.o:fpi.f:(.data+0x30): undefined reference to `mpi_wtime__' C:\Users\Troy\AppData\Local\Temp/ccUROg3z.o:fpi.f:(.data+0x34): undefined reference to `mpi_wtick__' C:\Users\Troy\AppData\Local\Temp/ccUROg3z.o:fpi.f:(.data+0x38): undefined reference to `pmpi_wtime__' C:\Users\Troy\AppData\Local\Temp/ccUROg3z.o:fpi.f:(.data+0x3c): undefined reference to `pmpi_wtick__' C:\Users\Troy\AppData\Local\Temp/ccUROg3z.o:fpi.f:(.data+0x40): undefined reference to `mpi_type_null_copy_fn__' I've try to run mpi.exe with mpiexec. It works well. I've also reinstall MPICH2, but get same errors. What steps did I lost? Could anyone give me some advises? best regards, Troy